As anticipated in last years annual report the MPR web site http://mpr.nci.nih.gov/ has undergone a major multi-component improvement in infrastructure this year. The most fundamental change is from the Microsoft .NET framework to Ruby on Rails (ROR). The rationale was that the proprietary.NET architecture has not evolved to be nearly as efficient in implementation or alteration as was widely anticipated. In contrast, ROR is a very powerful, open-source framework for developing database-backed web applications. The emerging evidence indicated to us that ROR was on a trajectory similar to that of Linux in its early days, and was becoming the framework of choice for database driven web applications like MPR. This rewrite provided the opportunity to incorporate enhancements. For example: 1) in MPR.ROR literature citations are displayed in each context where a phosphorylation site is shown, rather than in a few selected contexts in MRP.NET; 2) An enhanced search for molecules is incorporated; and 3) Internal data retrieval is based on simpler, more robust query strategies. In concert with the rewrite, hosting has been moved entirely to NCI Servers to assure reliability. A big part of this effort was working with staff (employees and contractors) of NCIWeb to introduce this new technology to NCIWeb. While there was a wealth of documentation for Ruby on Rails deployment, very little pertained to NCIWEB configurations. Thus, significant adaptations were required. In addition, systems security has been markedly improved, facilitated by security scans and technology in place on the NCI servers. The new MPR.ROR is being deployed in early October 2008. Concurrent with these changes, content has been culled of antibodies withdrawn from the market, and augmented by new antibodies from 7 companies. Several of the companies with the largest numbers of antibodies have purchased by larger vendors. The required URLs and identifier changes have been implemented to maintain direct linkage of the antibodies to the primary data from the suppliers. Background on Ruby on Rails http://rubythis.blogspot.com/2006/12/justify-your-choice-of-ruby-on-rails.html http://www.oracle.com/technology/pub/articles/haefel-oracle-ruby.html